SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ef968965a9f642751afc88fc8f1f421bb9ee5f1010a9d1eb243122fb1296569' 
  AND token = '+qLXB+IQmO+veQTyA/9ucXNi5/359qx9lIvIp6t4KSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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