SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ea424fd2e7790f7ccb24e6ccc1c70949814ea0f5322c53f0813baf1dcd19e8' 
  AND token = 'heYOzZIbE1+Wm2PEo3okoXHlo0oQShVOAI43BBmVCHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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