SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df6b7ff88fa923aa7640eaa551f127d539c03bd21da9d348aa5b0658f6d9edb' 
  AND token = 'GmzkHyFmKSvvIplFTvKfFydcqYuZ52lZB/N/LMre0FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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