SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98b5d2d66c33561ed041cf1a680374784b843de30c0192671f811caf9334446d' 
  AND token = 'CglWuiZr1ulRapP/nd0rGqD891h/eRFEYVb+JKK0r74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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