SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '31bc5da606ae841e6708e66044e05af6738f7fba38fc3491caf87f54b8d86cad' 
  AND token = 'SM29bKkZR9hjE5vdaURr6GCosKgQpfiJEumuY0mWZV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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