SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9936ba746332eb8baf3811173ad4a43a8596aa53e740be0d19fc1e0f2935ca93' 
  AND token = 'a9gn3rG7scbM/fe2iB2RkZtQHhI6Hijk5UwyXHvDPas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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