SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0e2070f2668b073fda58e3eec5c519cda1e3c0927153aeea5c5dde900aa3002' 
  AND token = 'zPb9cZA0+LHRoqLCc9ZuipH/dUBpW6qYTpAaxigxgC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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