SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c3fed742c242e0c10e1a4cdf6e25f31af5aca805d481a145d4cf1d483581755' 
  AND token = 'PzLJH+znSeAiVcxdSUwvO8kcTWdZPsT1oLrcKdjyQZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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