SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58a38dfed0f0dec8b598aff2a1c350b166a35b0f5d21e2e80906de1439466c17' 
  AND token = 'pL7yoO5kfWA2Ox5JgveLSmwZCwtaAMTS95GgPvVeu+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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