SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0983da7e4aead8f12e7533ce7b871f734b64df98743867706997c147ea4626f' 
  AND token = 'slmP+QbN5zFUrBDROhK+b/TPjDKRlndnihXhxIZ5kpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}