SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56ec9159831b837c4b323ba1244f0bd4a4e947054b23dfadf1eecc404be22305' 
  AND token = '4Dnh+00naF/tuBTtIo58oaXAwGnaOJEtWPldNfpvazU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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