SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '162f763358255788c07289db065e82728ca2c43e624898a79c67b4c46e4c72bd' 
  AND token = 'QQHaldgVSgt7yJZEqWOYdcsSt0JyK7fbzFxX482m9iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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