SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56eda38df94480cedf555cdfee8464ab1753ee9b4349acae7b32072a5fbc16f9' 
  AND token = 'C+zcoUQG7XXvFaDcuSXYEYy+KvPSsiDzlA+bCNkVeIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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