SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acd2d02770b41150294e4a7a52498a628da7138b2d13f69e8ff0fc70d9fac391' 
  AND token = 'MehtTlHNhJFZPg2VXs4d6BiL0nylrhZTrgEVPsLFB1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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