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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b43aa91a1e2870a7357b47b64d3e64e70ffebf0053efc511f3e6ee2dfde9a8' 
  AND token = 'UvihN6ebDWb2q5HgcuRo4u4ifd0ARlTpQQasjdl/Mik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}