SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d98563b661e5d7749128bf23087014fb66675803e6d72a3c875e04bc8deb4fe' 
  AND token = 'seJVurNEcQJZoS9Avobmg1jB0cJDwbXGJW98fviWww8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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