SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea9dc0ec9fde61b86bc410fc140a7104e8cf528749253853c049170c54824af' 
  AND token = 'Tqif6aRWlYlnhaVbQjAb27qCDGUAJ90odCmgHLa7yeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}