SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cd1a04d52d01279249df3bdcef16ff6700e4f325b5beed768ee2bb8f035cd85' 
  AND token = '61LPXXAzi1QdyxBOBMO/bZTSKOftWAN8fd92hjaYQi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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