SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '449b2e48beb4cec38543774b8b62edb21b2f8cfb2919d06c21a9261811108fd9' 
  AND token = 'QmxhQalZfPNKuztm1i+pGs1ZRpchLZXQBIpGMKXomWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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