SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6076777f29b3d63fa8d6f3bdd393a1bfd96833e1423a3473c8a09c2d58961e2' 
  AND token = 'pYWh5IIoFrK8whEVMo1yXZLE1T/zPaxozu0PF9aAzRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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