SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b57031f57d519d55acd3e1306d0710dbecde2ddc58ae8a146f452a33bbdb8f02' 
  AND token = 'IDI0v6S9AHUJXNvkAkTzUoOIAfh9mQV+KLSEzlzB/BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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