SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '723c815c2814d57160ff7cce3bb2e23bddf784fa3cf0aabe9a42d71f71760ccf' 
  AND token = 'C8da/rdIj0X42qgUKaNsZzT1aEHO5w0TWz16YRgXuPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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