SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f09b036e68dfd4677397b62c05df31eb388f8adb24762f99cccfbb4450f2e552' 
  AND token = '9IzyJPHZqTaH8iVe4t6xBegHhcAohTjv29W5oSEZzKw=' 
  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"
    }
  }
}