SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675589a253c2794fe9eed4e4cfa472d2d9513b2d8dd4ff10985a7906927c9dd4' 
  AND token = '7FI6gh6CSlZTn21XaCYyWTv+K8WlEYvLWK7LU2yLPBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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