SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe8a98e326625b134fb439fde8a3b24d75088d2febbe2c65191a57612f35f42' 
  AND token = 'w2YipFPHhIXdiaYQXKiv1+KRCeQaldhPKNbjPuWMWsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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