SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04846e775a407a2244d9a8e2f2644636a7a3489e92e804d04a7be1fb8aad961d' 
  AND token = 'XxgJ6R45C7lzxCLKhgzYpRr66VFOvpEGCxiqY6/D+Qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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