SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f646981e8740fc0197f8c42149e74b238d954cea59e781e5910bceae670a8a8f' 
  AND token = 'LXOKz3V0MH9RJUjCVwYNKGf+0ZXN/TC2uOFyLScYrrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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