SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '100912dc7abe9afbb5ec9fcb168793b9ea81489009dbad66d55cfb722139a50f' 
  AND token = 'rOFoeIlokHXCOqbk3paYmitPOLHhvkfwHOiimyQc0D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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