SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21792706cbf52cbb1d55da8802fb82c1a9dca1062b6a613fbccd2aa50aa38153' 
  AND token = 'kTk/rrLqizGXJdGPwbKiK1EAqgC56G/iDjcIUjOOhq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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