SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c13e810a11203528848e4ba49d5116e581242626fd2995673634af0843ec017' 
  AND token = 'xbS52ChwM8aLldkZ3o12ReMk6PWRqOKEhAYtHGOL9Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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