SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42016cb935b9888286d95d61b6642543f0aabebdd093b1aa58a03058c1f03348' 
  AND token = 'XuQlyGEVUoYss+zn0W9QWwCvN5pjV9qzCLj6/PKTDWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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