SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '643b2b13083d678a1462b8b89d4f2adf04d09247cbdb104a94c54446cfd7c90a' 
  AND token = 'RfeMtoeKqBr1+vUdPbQuBJcFCLpBzYUduwF1VHRzcXA=' 
  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"
    }
  }
}