SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a8b18e295c9204f3393fd7afb43ef5145f160c32e4e93a43dbadaee73a20913' 
  AND token = 'yKlBqO2wNvrZ4bII60A2kAZN6p3G+4peQQc4zYyFRHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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