SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '277b6483a6bdf9f418d06b23158174a5642765f757b84b04b247994232cc05a6' 
  AND token = 'S43Q6si43Tfco01xBCiFVTu+na3wZWToe88lLjD4ifU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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