SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de8317d5416a626ac10e2fb7f8ea8598666139c6cca10a1d2efdf4009e69469' 
  AND token = 'fRjBqnnq0muOCMjTWf46ZKPDTw3IgH7AjrJqVo9zvgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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