SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1aa3b718d909fa0d0f1f0ec4a12caebf75a8370ee67e24705596a6692231be61' 
  AND token = 'KulPvbI8fg149B1kAOkPBBaoNyyCKnyMEP1x11etyEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}