SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47de709a0a717e2b8b8ff44bbe8384e0acd71b82de3e25be572eb91135a366f3' 
  AND token = 'mXJlzvRJ779tueFZIzLHXO1POElgMMl7hQUpSJvKkAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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