SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cde138ecff2c4c0aee121c28c2f377bb16c9c41b26fc50a356e51a4acca03d57' 
  AND token = 'iglK/JLmV6PS8f3ih5LbcKqe5HcUxj4kE/xy8OpiI2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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