SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad2ab1d59732d1992de2e812c7c10dd62a21dcfdec4f21d78367be629dd2bea5' 
  AND token = 'qdiCpTwqJJrQhvSP7nuEQM5vYA2FKt8HAi4vZoQ1wHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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