SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c79d988a289a2a83de904d6db41d4c5f1f67b9284b247077ee78951ee5082d7' 
  AND token = 'pghZv/ue9lvrcvcALlfAFKi+IHwKKVx1+Fsy1PF3+Sw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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