SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06539594c86281dcfd13d8e8c0bb1697eb914a5aad7746a5916908d728a639fc' 
  AND token = '68RuHSf8uysbpUataLKR0GsC2Ho+CYiSYObrsB0IWSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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