SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '149f376fbc2d89c8a0f88f4f522526bd999dd9ccd0b53e3272adc517835d2989' 
  AND token = 'fuw6nXEaXrAhAbm/HGp/O2FZhmViSXZKbgWeQj5oM4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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