SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7f0b95e3ae0e36078639adb0544ff0554a43cb92258d51c2bc08c7afd77e157' 
  AND token = '2mqFMm2gsJUlPoiGiZPVb5/kPpgyh8h9+A6EuzIiOfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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