SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8030d5d572b71a831e589d34e57e806eed9e84b7c18541ccfbc576b5d02a3029' 
  AND token = 'QsSU1MrR6Zq2AKmKgsDHLvd+gEkN60aGquZojJSv4V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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