SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce6cfaf939fe809d1b0da5d995187362554cd217dc897b200a0760db6514f9b9' 
  AND token = 'oSdiPHjbicJGD5eLlT60uyKCPkPvW0tgv/nlXJwa+t4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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