SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0b9a715c87016104f5bc831c1b2728e92fa135cd0542e2a4ec740898ffbd821' 
  AND token = 'pKGErpKodjavc9p7YciMBWUVmvAO419tPhfwKlX1DTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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