SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f6ba2af378136389ae38bd7a1646ffb4fcf13a1883542efec08f657a5365b422' 
  AND token = 'psLZeEjWGMNq/fTZeU9zi8VTIehkPZrhrkQMKHuYeew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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