SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b1632e4ff316f84f97deca204a7dcf876eb2610d15e7d824dd287890a29e4fe' 
  AND token = 'dQEE7GUVqjox6+FsCJ++v/kSnvspHSnuE/CNqiCcqDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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