SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd0999922d13198b3463ffa4f9f36b2f0f115e82ac3fd14af07dac332d98f412' 
  AND token = 'R8HGUAcWeFnY7dBYFYTsJpuWgIoDepBex8BN1EOBqmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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