SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8a24d0d44295ee3d3f8181fd27f608cf94dcf03f7d74e868aeb246d7e805b2' 
  AND token = 'AdJNf5p6pY+xyumITh2ZyGPK/IQ7/SloIz0wwAVrsrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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