SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b18389113f0cc6b5b5ba71ac1945a31e306b929bf209e40819e5d755b6203d' 
  AND token = 'UhMvvpOtjX0Wnr8nxzBOwPDYUHCooQGIqOKQLW1o37o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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