SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c5ccbdab666510988220837a4e58cdebee8c5f62f845cb5f86a359a42da3d2' 
  AND token = 'K/aOERSMWGUysvbgiLmvsmwF7eZ906X+sJBpMmW1nJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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