SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5813291c460e3dc2d655d93ca5fc32ad9d53d6c52e2a0510cc990bdfca8c3cb2' 
  AND token = 'BMcEM15GPoUkIj7N7fpJCqpNmU2NNBv5s0gxEseyuMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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