SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f408bfb4f3b6ea4bb86319a0c7b99e0bf4db6e705381dc037a060d4b931f822' 
  AND token = 'OYqzlQraLAF1VdqOXhFpQcpby07BtWLGObF0xKkqJH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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