SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b962d7182130da633dc663644a906405bc24969d778925251e01a09d884886a' 
  AND token = '+7naYNvQo9+GgJGeOXuQFdzzPuxagGjS9zJl4M7/Czk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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