SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23fe55ab4143074d92195a93a5c261c18be6b7f7859d28770161eb380ff0f9dc' 
  AND token = 'yfFKYyidO5CUu5T6DGY7p1+5BJHNB+xXe5eKyWyPrnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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