SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '478499c47bd45b3166024c7fba93f6af9e94707d14351ac9bbef247d6c9bf405' 
  AND token = 'YB3TJI74w+rr1GSRT/W6bQJpRoiE1NFWuQBFyEtCAFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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