SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b64b8f193306c890323d0c4a42f23172073cb85b8c7eae6a7535f4e4610ef724' 
  AND token = 'F2Suq+stWPTit+gwVpNdZNb5dTNaFZthaUGCOTjUkYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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