SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cf097e54b2e6001d1f76c31d013f240162589c78d9f887be5f27c142fea797a' 
  AND token = 'yvyP+yVOpDCuaZEyOIxtlxxr7jye8AKBYTghwPEhjVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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