SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfb27911baece1d1d0b90c68f8ecc316c72ea1a72b82eeeb2c20c7ae2177796a' 
  AND token = 'CwSshWSfFhu2ubtYIlWPMTz342wzbxRNLF1uvXq/H2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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