SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11848fe40fcb8c8a4691142f9be2074cd9eac7fe5112c391ad5751cd5eded465' 
  AND token = 'prF21vqWo8cKR5nfqe9i7+reO5PpU+cv/I40lqPiFGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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