SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d5832cfed6bddf9d646f65c40e26b7e2506bf5e9be72ca1ee01db039320480e' 
  AND token = 'C/kbbd6iKndw6eGaZwiMptB4icfMFL6fx+nwmPk6nm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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