SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '657cf955b86bd6127aef946110d836c7387ea52c31b9e6529cd2079d3b5afead' 
  AND token = 'OSANYw1X7NFY4QuJvNB0LG7jVhPRY7m3JG+DnnUnhj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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