SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f84299354532d653433cad012b7ba7a18df117f8258ef1bcf46f54a3c083104b' 
  AND token = '7TGjEBiWOts4Jek/wvyLg7/RuHoZBYiIKkdv7czrz94=' 
  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"
    }
  }
}