SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae294de054218151313c5024e084074bf928617615a71fb085a8ea84d2a20100' 
  AND token = 'O3hHia0tGvmzvLUJBrYOMp6hjTUNbnM86Cjtp2hFlfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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