SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f86ff1f889e75f917c56c6057408fd5ad2293ad67d5784a6cfcea9f6f9d43da' 
  AND token = 'aTfjQFdkBOw54L0xNBxX65lna11JyH18Blm/deQFVs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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