SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90439ebbc245f2fa38ff9d733c150386349e58a3f5d9cd1bfb5795f5b8a7440b' 
  AND token = 'r5ZHoiVOyrInJEvdnMp0yXCB6tYBBzq0/ou78MUdb4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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