SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eab0fee8ef9f1783165a38da6f1da975c70fa9a88098966a525755036ffb2308' 
  AND token = '2zguIUn2pYNOQhBcifkDIM24bOCSOqfTXtWgBM1u0HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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