SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ac8fb944a82425064474d08634a457a5614ed0900a176e196b600461b5bf4d' 
  AND token = '+5MocMMmF8pfYbqYmQF46J2AtbS84DBK0Ux9uCeX9ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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