SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9028ee30001a87aca1b11c3d602827b31359c66db1b1e56f4919b4a5802da9f9' 
  AND token = 'v1cZvmkYez5ZFjqLAPVMIhAi/+l+d+RyfbJfBujtsO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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