SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '783cd0340baa390343f2cafb9b941c3fe39ea0359ceeb1c415e126f56ce8a18d' 
  AND token = 'MBrw53hEdewib4vIU95ARZnB0ZXmMVkheC4+plxpKiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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