SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '516a2b6d7ef87939474508a1596d92ed6209ae84501fcd31c65b63c33c74a081' 
  AND token = '9jWxjJ4AdoJ0qsrQLRFSTwJ7nOQY/BP8/3uomvM6q68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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