SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a8cebdc6f4f12e9a9d637d8c36792c0c1953a2fe7a336f712620450bc38316e' 
  AND token = 'lKybvXxFknfPx8pgoKRT+Jbubwz2pGx2jZWeo3nFvs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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