SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f432f90ccac43317a594fc23270cd6327e14e6f5a91b307c7e8596c18cd68a9b' 
  AND token = 'UvWQkFhmhulmZ9GiTihQEIXxMDce/UjW6pHptSNWu2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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