SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de274b8a2518130fd6d772c41af5364b7f47a1c1d2ad7b9992dcecfc8267b3c8' 
  AND token = '/cN+TT6YUvk4hhKpxBkpLLvC9Jyp8RKGkQvy5LVUZAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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