SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a536e8f206ef6a75804029b35632791145c0929c5e759c486ef3ccde4ca8881' 
  AND token = 'lkJtkCNlehsAsRXNk3Zs6symB8JhYfTZn0+TJpI/8OE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}