SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ba5ac01c579a51343d26f09b4c365a3e3e59ffe5a76d4257d22a0fed602f7b' 
  AND token = 'BJAH4bdl4BsXojAjhcGXo3MIKJUYJqwyBW5MSLiGQBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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