SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d2cba38580f910b826682b963d7f934211295722e9ab22403ff046bb992fef' 
  AND token = 'Sca/OOvuSS/go8RWiPngPahwp9jVx/jtJUsTsGAbnXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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