SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c8aed160e697654bf9d603a5c16e436cac60cff6552c27495b179fa582ccafa' 
  AND token = 'TYPUQyMUmsO/XjzsScc38beiBeHhykO8NtsJsBymuo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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