SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '748f1906128d6e415dd49e71733da9f57df1b10241dc2e78062eefeaa7126896' 
  AND token = '+CU4eh3RPmx/QPKbvVRgZg5RYa8G5XcH+wAzFGczR3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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