SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020d77a09b92f4ccab0ccd18857f534c3c66809511abb423114f1a6c68b4ea5b' 
  AND token = '/iU9I8u0KmJMbfiAhmYBGTPOzyfnsy7ZAMGsLRAVPVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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