SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b6328d263c1b2df2d90c4a6f2202bd3121a16b7877749c745a6c214d066ecf' 
  AND token = 'w/lsBRS5UpKfp3a+NzHbUj6ulU7vd++KkJpwBN3Vzmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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