SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a5215762f76989caa41811fdaa1726c105f60078091dd7658d06260ba5c51d9' 
  AND token = 'Hgi4ZPnUjftwA5qlK+/jdvExtdzprqrLUAnTjHYttOk=' 
  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"
    }
  }
}