SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca8b370df85411939fe3d72fe401424dfc84007b590a19a82bb257203a1d1f38' 
  AND token = 'wV83BtgLz4VSrTirc37G4lLp6JZxkyWEbq5nDiNTVXQ=' 
  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"
    }
  }
}