SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371fc9ae06add8338d0f92eb9c8857733586f662850a08a32d46a27e7b4e6bb2' 
  AND token = 'rb4CKv8rBqg3s+ym99kwQ7BavkfZqB0xsR6Z/hxjqug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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