SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5138080f16fab279fe6c16b03bf26d7deaebd39d545556772360fb4f7cf7fc8' 
  AND token = 'IffYO2fTZb453BKzKLYQB8VVZlODp4uvZ6aaPBmCl1w=' 
  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"
    }
  }
}