SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d13312401f648f459361f89f1140aeaf7488aed7ba51679e72a8f408649c5a' 
  AND token = 'AY52O3bBjJLoFMGtowzCFPrM3xktqHjGQCI0CVMUpX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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