SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2ff0fb9482601243468a68669931cb60752788551ab2843fb58ff5d48d1a8f2' 
  AND token = 'I5+kNm9CioJalbo8Zhipw53wX5VVZ2HkVBWG3gyihHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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