SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6699400a0e1331edf0f92711a1c99cd5d472e222203cf7b873fc636faed7c18' 
  AND token = 'oYWPohsVmlvgV9Y/FHQsU/1syFw4RXBIh8CK9wDva2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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