SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c97c3026ccd715ad949030811c680eedd2435ccf31f04714b0b666ae906db18' 
  AND token = 'UJ8GhVrsLQ9EM6Z/E6gL/2CPn9Q0+LqI4vwj2bsOAj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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