SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dcae2acd4aa360303085f952887daca0e351a5a9e8b8a6de84a498f45808611' 
  AND token = 'DVoNHeQOjmnh9phZJb7Y1rtCq9zt2ERfBHopWEWJ13Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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