SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fde6519aad15491dbc1693965a3e9752f45610224c682dd8b27d42973cf9c5b4' 
  AND token = 'Jl8+9lua6TtHvGhrMbaj+gJ0QUfVt0PShdJfHmubZcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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