SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6350bdffab86a7ce1364b20fe67359b355b89acbedaaaf4ee9afd5dc5668a6d8' 
  AND token = 'FzThnUPaDVdttMHFHPll3+MXnJ4CY6MIicc/lqF4G9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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