SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4554f6e74217a836b5a5212dc4ab6384005c26a4a7533fa3bc54e3fdce6dc07' 
  AND token = 'Rm8HkWgBWvG7vpxrKVaBBrzRPHvnWvOX0eI23lv8uWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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