SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e166ebddd4cb85082087afdfee26a7bf269324870e6504c5f7d74f723d4f2412' 
  AND token = '293n6tykJ1msxBdfigGplsKsUeZtjiijPLn4su7VqrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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