SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f67b101266b35a6885f118b4990bc28bd7cd80e1164dec0913b3f419df0674' 
  AND token = 'sl8zHRi+AoDpahDYMZJg/cHrhzkpZRfn980xqLSbBsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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