SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a89df3091e8f68925713553c7672b71b89142c93ef47c90279a6cfe149d21bd' 
  AND token = '/oOjIXBfUhInciv7M5BS+Z2jg7Byz8mddrSVUShzqNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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