SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '949260c23e639806075512c95145f1efe91d5f940e96f66c777e3fa2141d2943' 
  AND token = 'j0RDJbZxpnqGp9PPti3XhBcEtLvPO/JLQSmpSGYMMFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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