SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd68b3952aa78c8710040f46a654ce07b26e149052042aba4665ca8929dc4b6c0' 
  AND token = '4qEdvOw9EG613OrruFcue+/i7wOOyzMKW/kKsvzBFCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}