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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1ae89327ac6f670e1dedf9321a908dcc336ea4b08845b662357e1af754ba8d' 
  AND token = 'kLXo51tw/Yy8Q2N9CoA7xp2MrTR9qIPDCNN7nwSXXCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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